there's plenty of confusion and misinformation out there, and sometimes, even the laws are confusing. links to various websites are wonderful i suppose, but, sometimes it comes down to an interpretation by a dot cop.
i'll try to give you honest answers, with explainations as i go. i'm sure some of this won't apply to your individual case.
a vehicle that has a RATED CAPACITY of 26,001 or higher, requires a c.d.l. license. there are exceptions for emergency vehicles, but little else.
ANY VEHICLE that is rated, or hauls over 10,000 pounds gross weight and is used for business or for hire, requires a d.o.t. number, and the owner is required to keep records. this is where it gets tricky. "business" and "commerce" can have loose definitions, but in the strict definition, that means ANY form of payment or restitution for services rendered. if you haul your buddies broke down car on your trailer, and he buys your gas, or, lunch, or offers to fix your plumbing in your kitchen as payment for your good deed, then SOME cops will see that as payment, and if you are stupid enough to tell the cop that your buddy is buying the gas, you may get a pretty stiff fine. i saw a perfect example of this a few years ago. i was working at indianapolis raceway park, and a d.o.t. cop was writing tickets to every competitor who was pulling a race car on a hauler trailer that didn't have a d.o.t. number. the cop told every one of them that if it was POSSIBLE they could win money, or, a trophy, that was considered "commerce". the tickets, all of them, stood up in court. i think the cop was told to "knock it off" by his superiors after a howl of protests, and the threat by track officials to ban the state police from the grounds.
still, the tickets held up in court.
in all my years in law enforcement i have to tell you, most people talk themselves into trouble. had they simply shut up, then nothing would have happened. in the end, remember. A COMMERCIAL VEHICLE IS CONSIDERED ANY VEHICLE THAT IS USED FOR COMMERCE, AND COMMERCE IS DEFINED AS ANY FORM OF PAYMENT INCLUDING SERVICES. a good idea is, if asked, to answer "i'm doing this because i want to, and i'm not receiving anything for it". oh, by the way. if you run a d.o.t. number and travel outside a 100 air mile radius, you have to have log books. fun stuff, huh?
back to the c.d.l. and the rules. in some states, indiana being one, a vehicle under 26,000 doesn't have to stop at a weigh scale. in illinois, they do. i have seen a few old trucks in different states with signs that say " not a commercial vehicle" painted on the bed. in oklahoma, i've seen 1/2 ton pickup trucks with signs that say "commercial vehicle". check the laws in your state, and i suggest you get a copy to keep with your registration.
finally this. remember your vehicle gross weight rating can put you overweight should you load it too heavy. the same applies to a trailer. in indiana, a person can plate a car hauler with a 3,000 pound plate, and it's legal..... until you put a car on it. the combined weight of the car and trailer must not exceed the rated weight of the license plate. this same rule applies to a truck pulling a trailer. once the combined weight of the combination exceeds 26,000 pounds, a c.d.l. is required, and since it is a truck and trailer, a class A c.d.l. is required.
yeah....... i know........... clear as mud, right? in the end, good advice is for you to check the laws for YOUR STATE, as you are governed by them nomatter where you travel, and keep a copy with your registration to present to law enforcement should the need arise.
